A more thorough explanation:

A marital deduction trust is a type of trust that allows married couples to transfer property between each other without incurring federal transfer tax. There are two types of marital deduction trusts: a life estate with a general power of appointment given to the spouse or a Qualified Terminable Interest Property (QTIP) trust.

For example, if a husband creates a marital deduction trust and transfers his assets into it, when he dies, his assets will pass to the trust free of federal estate taxes. The surviving wife will not have to pay any taxes on the property. When the surviving wife dies, the assets under the trust will not be included as part of her estate, which means her federal taxes will not be as high as they would have been without the trust.

The purpose of a marital deduction trust is to protect both spouses' assets and estates from federal estate taxes. It is a useful tool for couples who want to ensure that their assets are passed on to their loved ones without incurring unnecessary taxes.